347 lines
8.3 KiB
C
347 lines
8.3 KiB
C
/******************************************************************************
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*******************************************************************************
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**
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** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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** Copyright (C) 2004-2010 Red Hat, Inc. All rights reserved.
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**
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** This copyrighted material is made available to anyone wishing to use,
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** modify, copy, or redistribute it subject to the terms and conditions
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** of the GNU General Public License v.2.
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**
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*******************************************************************************
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******************************************************************************/
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#include "dlm_internal.h"
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#include "lock.h"
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#include "user.h"
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#include "ast.h"
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#define WAKE_ASTS 0
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static uint64_t ast_seq_count;
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static struct list_head ast_queue;
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static spinlock_t ast_queue_lock;
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static struct task_struct * astd_task;
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static unsigned long astd_wakeflags;
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static struct mutex astd_running;
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static void dlm_dump_lkb_callbacks(struct dlm_lkb *lkb)
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{
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int i;
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log_print("last_bast %x %llu flags %x mode %d sb %d %x",
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lkb->lkb_id,
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(unsigned long long)lkb->lkb_last_bast.seq,
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lkb->lkb_last_bast.flags,
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lkb->lkb_last_bast.mode,
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lkb->lkb_last_bast.sb_status,
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lkb->lkb_last_bast.sb_flags);
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log_print("last_cast %x %llu flags %x mode %d sb %d %x",
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lkb->lkb_id,
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(unsigned long long)lkb->lkb_last_cast.seq,
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lkb->lkb_last_cast.flags,
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lkb->lkb_last_cast.mode,
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lkb->lkb_last_cast.sb_status,
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lkb->lkb_last_cast.sb_flags);
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for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
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log_print("cb %x %llu flags %x mode %d sb %d %x",
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lkb->lkb_id,
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(unsigned long long)lkb->lkb_callbacks[i].seq,
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lkb->lkb_callbacks[i].flags,
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lkb->lkb_callbacks[i].mode,
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lkb->lkb_callbacks[i].sb_status,
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lkb->lkb_callbacks[i].sb_flags);
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}
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}
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void dlm_del_ast(struct dlm_lkb *lkb)
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{
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spin_lock(&ast_queue_lock);
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if (!list_empty(&lkb->lkb_astqueue))
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list_del_init(&lkb->lkb_astqueue);
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spin_unlock(&ast_queue_lock);
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}
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int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
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int status, uint32_t sbflags, uint64_t seq)
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{
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struct dlm_ls *ls = lkb->lkb_resource->res_ls;
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uint64_t prev_seq;
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int prev_mode;
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int i;
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for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
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if (lkb->lkb_callbacks[i].seq)
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continue;
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/*
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* Suppress some redundant basts here, do more on removal.
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* Don't even add a bast if the callback just before it
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* is a bast for the same mode or a more restrictive mode.
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* (the addional > PR check is needed for PR/CW inversion)
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*/
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if ((i > 0) && (flags & DLM_CB_BAST) &&
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(lkb->lkb_callbacks[i-1].flags & DLM_CB_BAST)) {
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prev_seq = lkb->lkb_callbacks[i-1].seq;
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prev_mode = lkb->lkb_callbacks[i-1].mode;
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if ((prev_mode == mode) ||
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(prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
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log_debug(ls, "skip %x add bast %llu mode %d "
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"for bast %llu mode %d",
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lkb->lkb_id,
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(unsigned long long)seq,
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mode,
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(unsigned long long)prev_seq,
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prev_mode);
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return 0;
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}
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}
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lkb->lkb_callbacks[i].seq = seq;
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lkb->lkb_callbacks[i].flags = flags;
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lkb->lkb_callbacks[i].mode = mode;
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lkb->lkb_callbacks[i].sb_status = status;
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lkb->lkb_callbacks[i].sb_flags = (sbflags & 0x000000FF);
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break;
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}
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if (i == DLM_CALLBACKS_SIZE) {
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log_error(ls, "no callbacks %x %llu flags %x mode %d sb %d %x",
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lkb->lkb_id, (unsigned long long)seq,
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flags, mode, status, sbflags);
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dlm_dump_lkb_callbacks(lkb);
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return -1;
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}
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return 0;
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}
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int dlm_rem_lkb_callback(struct dlm_ls *ls, struct dlm_lkb *lkb,
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struct dlm_callback *cb, int *resid)
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{
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int i;
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*resid = 0;
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if (!lkb->lkb_callbacks[0].seq)
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return -ENOENT;
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/* oldest undelivered cb is callbacks[0] */
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memcpy(cb, &lkb->lkb_callbacks[0], sizeof(struct dlm_callback));
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memset(&lkb->lkb_callbacks[0], 0, sizeof(struct dlm_callback));
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/* shift others down */
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for (i = 1; i < DLM_CALLBACKS_SIZE; i++) {
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if (!lkb->lkb_callbacks[i].seq)
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break;
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memcpy(&lkb->lkb_callbacks[i-1], &lkb->lkb_callbacks[i],
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sizeof(struct dlm_callback));
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memset(&lkb->lkb_callbacks[i], 0, sizeof(struct dlm_callback));
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(*resid)++;
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}
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/* if cb is a bast, it should be skipped if the blocking mode is
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compatible with the last granted mode */
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if ((cb->flags & DLM_CB_BAST) && lkb->lkb_last_cast.seq) {
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if (dlm_modes_compat(cb->mode, lkb->lkb_last_cast.mode)) {
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cb->flags |= DLM_CB_SKIP;
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log_debug(ls, "skip %x bast %llu mode %d "
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"for cast %llu mode %d",
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lkb->lkb_id,
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(unsigned long long)cb->seq,
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cb->mode,
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(unsigned long long)lkb->lkb_last_cast.seq,
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lkb->lkb_last_cast.mode);
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return 0;
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}
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}
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if (cb->flags & DLM_CB_CAST) {
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memcpy(&lkb->lkb_last_cast, cb, sizeof(struct dlm_callback));
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lkb->lkb_last_cast_time = ktime_get();
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}
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if (cb->flags & DLM_CB_BAST) {
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memcpy(&lkb->lkb_last_bast, cb, sizeof(struct dlm_callback));
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lkb->lkb_last_bast_time = ktime_get();
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}
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return 0;
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}
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void dlm_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
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uint32_t sbflags)
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{
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uint64_t seq;
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int rv;
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spin_lock(&ast_queue_lock);
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seq = ++ast_seq_count;
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if (lkb->lkb_flags & DLM_IFL_USER) {
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spin_unlock(&ast_queue_lock);
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dlm_user_add_ast(lkb, flags, mode, status, sbflags, seq);
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return;
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}
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rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq);
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if (rv < 0) {
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spin_unlock(&ast_queue_lock);
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return;
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}
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if (list_empty(&lkb->lkb_astqueue)) {
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kref_get(&lkb->lkb_ref);
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list_add_tail(&lkb->lkb_astqueue, &ast_queue);
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}
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spin_unlock(&ast_queue_lock);
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set_bit(WAKE_ASTS, &astd_wakeflags);
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wake_up_process(astd_task);
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}
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static void process_asts(void)
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{
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struct dlm_ls *ls = NULL;
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struct dlm_rsb *r = NULL;
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struct dlm_lkb *lkb;
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void (*castfn) (void *astparam);
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void (*bastfn) (void *astparam, int mode);
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struct dlm_callback callbacks[DLM_CALLBACKS_SIZE];
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int i, rv, resid;
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repeat:
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spin_lock(&ast_queue_lock);
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list_for_each_entry(lkb, &ast_queue, lkb_astqueue) {
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r = lkb->lkb_resource;
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ls = r->res_ls;
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if (dlm_locking_stopped(ls))
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continue;
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/* we remove from astqueue list and remove everything in
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lkb_callbacks before releasing the spinlock so empty
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lkb_astqueue is always consistent with empty lkb_callbacks */
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list_del_init(&lkb->lkb_astqueue);
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castfn = lkb->lkb_astfn;
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bastfn = lkb->lkb_bastfn;
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memset(&callbacks, 0, sizeof(callbacks));
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for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
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rv = dlm_rem_lkb_callback(ls, lkb, &callbacks[i], &resid);
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if (rv < 0)
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break;
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}
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spin_unlock(&ast_queue_lock);
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if (resid) {
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/* shouldn't happen, for loop should have removed all */
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log_error(ls, "callback resid %d lkb %x",
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resid, lkb->lkb_id);
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}
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for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
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if (!callbacks[i].seq)
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break;
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if (callbacks[i].flags & DLM_CB_SKIP) {
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continue;
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} else if (callbacks[i].flags & DLM_CB_BAST) {
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bastfn(lkb->lkb_astparam, callbacks[i].mode);
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} else if (callbacks[i].flags & DLM_CB_CAST) {
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lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
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lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
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castfn(lkb->lkb_astparam);
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}
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}
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/* removes ref for ast_queue, may cause lkb to be freed */
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dlm_put_lkb(lkb);
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cond_resched();
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goto repeat;
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}
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spin_unlock(&ast_queue_lock);
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}
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static inline int no_asts(void)
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{
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int ret;
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spin_lock(&ast_queue_lock);
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ret = list_empty(&ast_queue);
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spin_unlock(&ast_queue_lock);
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return ret;
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}
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static int dlm_astd(void *data)
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{
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while (!kthread_should_stop()) {
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set_current_state(TASK_INTERRUPTIBLE);
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if (!test_bit(WAKE_ASTS, &astd_wakeflags))
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schedule();
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set_current_state(TASK_RUNNING);
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mutex_lock(&astd_running);
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if (test_and_clear_bit(WAKE_ASTS, &astd_wakeflags))
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process_asts();
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mutex_unlock(&astd_running);
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}
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return 0;
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}
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void dlm_astd_wake(void)
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{
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if (!no_asts()) {
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set_bit(WAKE_ASTS, &astd_wakeflags);
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wake_up_process(astd_task);
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}
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}
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int dlm_astd_start(void)
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{
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struct task_struct *p;
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int error = 0;
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INIT_LIST_HEAD(&ast_queue);
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spin_lock_init(&ast_queue_lock);
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mutex_init(&astd_running);
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p = kthread_run(dlm_astd, NULL, "dlm_astd");
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if (IS_ERR(p))
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error = PTR_ERR(p);
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else
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astd_task = p;
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return error;
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}
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void dlm_astd_stop(void)
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{
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kthread_stop(astd_task);
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}
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void dlm_astd_suspend(void)
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{
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mutex_lock(&astd_running);
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}
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void dlm_astd_resume(void)
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{
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mutex_unlock(&astd_running);
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}
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